Monotonicity of the Laplace transform for tomography in dissipative systems

Abstract This paper addresses the problem of tomography for the interior of dissipative materials, with a focus on magnetic induction tomography (MIT), a proven technique for imaging the interior of conductive materials using low-frequency electromagnetic fields. Processing MIT data is mathematically challenging because of the non-linear and ill-posed nature of the underlying inverse problem. On the other hand, the monotonicity principle is recognized as the basis for developing effective approaches. In this framework, the paper presents a principle of monotonicity for the transfer operator in MIT, i.e. the operator mapping the Laplace transform of the applied source onto the Laplace transform of the measured quantity. Specifically, it is proved that the transfer operator satisfies a monotonicity principle when evaluated on a proper real semi-axis of the complex plane. The description of the related (real-time) imaging method is also given.